Items you might want to bring:
Snowball
Dragon Fire
Wyvern Orb
Token of Strength
Magic Lamp
Heroes:
Cybella Gunslinger and Kane Grand Ranger can be substituted for Red Riding Hood and Vivi
Kai Assassin can be substituted for Shizu Assassin
Sven Warlord can be substitued for Lancelot Warlord
Gears:
Kai and Sven have to be wearing the Refresh Raid Set
All the Rangers have to have maximum Crit and preferably Double Strike runes
Tips on clearing Gold Mine:
Always just attack with Cybella first if the front 3 Gold Veins are 1*
As the front 3 Gold Veins become 3* and 5*, attack with Cybella, Kane and Sven. If any of them Refresh immediately lauch their attacks again.